1. Field of the Invention
The present invention relates to apparatus for handling hazardous materials in general and in particular to an apparatus for closing a storm drain, or other type of drain, in a fluid-tight manner so as to prevent a flow of hazardous materials into the drain.
2. Description of the Related Art
Among the most serious problems associated with the handling of hazardous materials is the accidental discharge of such materials into a drain which leads to a sewage treatment plant which is not equipped to handle such materials, or into a storm drain which ultimately flows into a creek, river, lake, bay, or the like. In either case, the cost of containing and cleaning up the material can be enormous both financially and in terms of the negative impact on the environment.
The manufacture of semiconductor products, for example, involves the use of hazardous materials which are usually stored in exterior tanks outside the walls of the manufacturing facility. Not infrequently, storm drains and the like which are used to collect rain water are found in the vicinity of the exterior storage tanks.
The material in the tanks is periodically replenished from a tanker truck or the like. If through negligence or by accident the material is spilled on the ground during the filling of the tanks, it could be collected by a nearby storm drain, resulting in the above-described adverse consequences.
Presently, companies seek to prevent the loss of hazardous materials in a storm drain by covering the drain with an absorbent blanket, such as a Spill Mat made by Lab Safety Supply of Janesville, Wis., or by surrounding the drain with piles of absorbent material, such as Safe-T-Sorb, available from Orchard Supply Hardware, Sunnyvale, Calif., either before an accidental spill as a preventive measure or afterwards to minimize the damage caused by the spill. Sometimes the edges of the blanket are required to be held down by some sort of heavy object such as, for example, bags of absorbent material.
When the spilled material is a liquid, the use of a bag of absorbent material, or the like, to prevent the liquid material from flowing beneath the edges of the blanket is not always successful. Furthermore, the absorbent blankets which are currently being used for this purpose are expensive and must be replaced as soon as they have become saturated with any liquid, including ordinary rainwater, because, after they are saturated, they no longer will hold any additional liquid. Also, the need to hold down the edges with heavy objects is time consuming and labor intensive. There are also spill mats available that do not absorb the liquid and are used as dams to prevent the liquids from entering the drain. However, where the liquid is hazardous liquid the spill mats still become contaminated and must either be decontaminated or disposed of as hazardous matter. Moreover, when not used to cover or dam a drain, the blanket or spill mats are usually stored in a pile immediately adjacent to the drain and is therefore unsightly. Further, if the drain is in a traffic area, the blanket or spill mats must be stored some distance from the drain and are therefore more likely not to be immediately available for use in case of a spill.
When loose material is used to absorb a spill, the material must be cleaned up after the spill and if the spill contained hazardous matter then loose material must be disposed as hazardous matter and further must itself be not allowed to enter the drain system.